What is the first step of DNA replication?

Helicase unwinds the double helix and separates the two polynucleotide strands

2

After Helicase unwinds the double helix and separates the two polynucleotide strands what is the next step of DNA replication?

DNA polymerase synthesises new strands from the two parental template strands

3

Define polymerase chain reaction (PCR)

The polymerase chain reaction (PCR) is an artificial method of replicating DNA under laboratory conditions

4

What is PCR used for?

The PCR technique is used to amplify large quantities of a specific sequence of DNA from an initial minute sampleEach reaction doubles the amount of DNA – a standard PCR sequence of 30 cycles creates over 1 billion copies (230)

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What is the first step of polymerase chain reaction?

Denaturation – DNA sample is heated (~90ºC) to separate the two strands

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After Denaturation – DNA sample is heated (~90ºC) to separate the two strands What is the next step of polymerase chain reaction?

After Each tRNA molecule carries a specific amino acid (according to the genetic code), What is the next step of translation?

After Ribosomes catalyse the formation of peptide bonds between adjacent amino acids (via condensation reactions), What is the next step of translation?

The ribosome moves along the mRNA molecule synthesising a polypeptide chain until it reaches a stop codon

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After The ribosome moves along the mRNA molecule synthesising a polypeptide chain until it reaches a stop codon, what is the last step of translation?

At this point translation ceases and the polypeptide chain is released

24

What is the first step of insulin production via recombinant gene transfer?

The gene responsible for insulin production is extracted from a human cell

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After The gene responsible for insulin production is extracted from a human cell, What is the next step of insulin production via recombinant gene transfer?

It is spliced into a plasmid vector (for autonomous replication and expression) before being inserted into a bacterial cell

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After It is spliced into a plasmid vector (for autonomous replication and expression) before being inserted into a bacterial celll, What is the next step of insulin production via recombinant gene transfer?

The transgenic bacteria (typically E. coli) are then selected and cultured in a fermentation tank (to increase bacterial numbers)

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After The transgenic bacteria (typically E. coli) are then selected and cultured in a fermentation tank (to increase bacterial numbers), What is the last step of insulin production via recombinant gene transfer?

The bacteria now produce human insulin, which is harvested, purified and packaged for human use (i.e. by diabetics)